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Effect of Thermal Cycling on Properties and Microstructure of SnAgCuCe Soldered Joints in QFP Devices

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Chinese Journal of Mechanical Engineering 2011年第4期24卷 561-566页

作者： ZHANG Liang xue Songbai GAO Lili zeng Guang YU Shenglin SHENG Zhong College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China School of Mechanical ＆ Electrical Engineering Xuzhou Normal University Xuzhou 221116 China The 14th Research Institute China Electronics Technology Group Corporation Nanjing 210013 China

Increasing global concern about the environment is bringing regulatory （European directives） and consumer （＂green products＂） pressure on the electronics industry in Europe and Japan to reduce or completely eliminate the use of lead （Pb） in products. Among all lead-free solder alloys, SnAgCu solder system, which has better thermo-mechanical properties compared with those of SnPb solder, is proven to be one of the promising candidates for electronic assembly. Previous work also revealed that adding a small amount of rare earth Ce into SnAgCu solder can visibly improve the properties and inhibit the excessive growth of the intermetallic compound layer. Thermal fatigue properties of SnAgCuCe soldered joints in QFP devices under thermal conditions have been investigated by finite element method and experiments. Based on creep model of low stress and high stress, corresponding creep subroutine was established for simulating the stress and strain response of SnAgCuCe soldered joint from -55 ℃ to 125 ℃, and fatigue life was calculated using creep fatigue life prediction equation. Moreover, thermal cycling experiments were conducted, the experimental results were found to be close to the simulated results. In addition, the tensile force of SnAgCuCe soldered joints decreased with increasing number of thermal cycles, and the fracture mechanism transformed from toughness fracture to brittle intergranular fracture. Moreover the tensile force changes and fracture microstructure evolution could benefit the quantitative evaluations of the mechanical performances of lead-free soldered joints under thermal cycling loadings.

关键词： finite element method creep equation thermal cycling fatigue life

Microstructure and properties of Al_2O_3 dispersion-strengthened copper fabricated by reactive synthesis process

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Rare Metals 2014年第2期33卷 191-195页

作者： xue-Hui Zhang Chen-Guang Lin Shun Cui zeng-De Li Powder Metallurgy & Special Materials Research Department General Research Institute for Nonferrous Metals

Al2O3 dispersion-strengthened copper alloy was prepared by reactive synthesis and spark plasma sintering（SPS） process. Studies show that nano-sized c-Al2O3 particles with 27.4 nm mean size and 50-nm interval are homogeneously distributed in copper matrix. The density of SPS alloy is about 99 %, meanwhile, the electrical conductivity of sintered alloy is 72 % IACS and the Rockwell hardness can reach to HRB 91.

关键词： Dispersion-strengthened copper Reactive synthesis Spark plasma sintering

A recoverable stress testing algorithm for compression and encryption cards

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第10期9卷 1398-1405页

作者： Bao-jun ZHANG xue-zeng PAN Jie-bing WANG Ling-di PING Network and Security Lab School of Computer Science anc~Technology Zhejiang University Hangzhou 310027 China

This study proposes a recoverable stress testing algorithm （RSTA） for such special devices as compression/decompression card and encryption/deeryption card. It uses a chaos function to generate a random sequence, and then, according to the random sequence, generates an effective command sequence. The dispatch of command obeys a special schedule strategy we designed for such devices, i.e., the commands are sent according to the command sequence, and the complete commands are put in a buffer for further result check. RSTA is used to test the HIFN compression acceleration card SAICHI-1000. Test results show that RSTA can make the card work continuously and adequately.

关键词： Stress testing Random sequence Chaos function Synchronization Concurrency

Nanowire-based transparent conductors for flexible electronics and optoelectronics

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Science Bulletin 2017年第2期62卷 143-156页

作者： Jie xue Jizhong Song Yuhui Dong Leimeng Xu Jianhai Li Haibo zeng Institute of Optoelectronics & Nanomaterials Herbert Cleiter Institute of Nanoscience School of Materials Science and Engineering Nanjing University of Science & Technology Nanjing 210094 China

As the necessary components for various modern electronic and optoelectronic devices, novel transparent electrodes(TEs) with the low cost, abundance features, and comparable performance of indium tin oxide(ITO) are inquired materials. Metal nanowires(NWs) with the excellent photoelectric properties as next-generation TE candidates have widely applications in smart optoelectronic devices such as electronic skins, wearable electronics, robotic skins, flexible and stretchable displays. This review describes the synthetic strategies for the preparation of metal NWs, the assemble process for metal NW films,and the practical aspects of metal NW films with the desired properties in various low-cost, flexible,and solution-based photoelectric devices.

关键词： Metal nanowires Transparent electrodes Solution-based process Light-emitting diodes Touch screens Solar cells

Herschel Investigation of Cores and Filamentary Structures in the Perseus Molecular Cloud

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Research in Astronomy and Astrophysics 2022年第5期22卷 109-120页

作者： Chang Zhang Guo-Yin Zhang Jin-zeng Li xue-Mei Li National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China College of Physics Guizhou UniversityGuiyang 550025China

Cores and filamentary structures are the prime birthplaces of stars,and play key roles in the process of star *** advances in the methods of multi-scale source and filament extraction,and in making highresolution column density map from Herschel multi-wavelength observations enable us to detect the filamentary network structures in highly complex molecular cloud *** statistics for physical parameters shows that core mass strongly correlates with core dust temperature,and M/L strongly correlates with M/T,which is in line with the prediction of the blackbody radiation,and can be used to trace evolutionary sequence from unbound starless cores to robust prestellar *** column densities of the filamentary structures are clearly related with mass per unit length(M_(line)),but are uncorrelated by three orders ranging from~10^(20) to~10^(22) cm^(-2) with *** width at half maximum has a median value of 0.15 pc,which is consistent with the 0.1 pc typical inner width of the filamentary structures reported by previous *** find 70%of robust prestellar cores(135/199)embedded in supercritical filaments with M_(line),>16 M⊙pc^(-1),which implies that the gravitationally bound cores come from fragmentation of supercritical *** the basis of observational evidence that the probability distribution function with power-law distribution in the Perseus south is flatter than in the north,the number of young stellar objects in the south is significantly less than that in the north,and dust temperature is *** infer that the south region is more gravitationally bound than the north region.

关键词： star forming regions-molecular clouds-interstellar filaments

Neuroprotective effect of chitosan nanoparticle gene delivery system grafted with acteoside (ACT) in Parkinson's disease models

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Journal of Materials Science & Technology 2020年第8期36卷 197-207页

作者： Yongyong xue Na Wang Zhi zeng Jinpeng Huang Zhiming Xiang Yan-Qing Guan MOE Key Laboratory of Laser Life Science&Institute of Laser Life Science College of BiophotonicsSouth China Normal UniversityGuangzhou510631China School of Life Science South China Normal UniversityGuangzhou510631China South China Normal University-Panyu Central Hospital Joint Laboratory of Translational Medical Research Panyu Central HospitalGuangzhouChina Department of Radiology Guangzhou Panyu Center HospitalGuangzhou511400China

Developing new drugs to treat Parkinson's disease efficiently is challenging. Here we report that chitosan nanoparticles(APPDNs) could serve as novel candidates for the design of anti-PD drugs. In this study, we investigated the effects of chitosan poly ethyleneglycol-poly lactic acid(PEG-PLA) nanoparticles conjugated with nerve growth factor(NGF), acteoside(ACT) and plasmid DNA(p DNA) for PD therapy using in vitro and in vivo models. Using PD cell models, we demonstrated that APPDN had good neuroprotective effects. More significantly, experiments using mouse PD models demonstrated that APPDNs could ameliorate the behavioral disorders of sick mice. Immunohistochemical and western blot(WB) analyses demonstrated that APPDNs could significantly reverse dopaminergic(DA) neuron loss in the substantia nigra and striatum of sick mice. This study opens up a novel avenue to develop anti-PD drugs.

关键词： Parkinson's disease Chitosan nanoparticles Acteoside Gene therapy pDNA

Effect of plastic strain and forming temperature on magnetic properties of low-carbon steel

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International Journal of Minerals,Metallurgy and Materials 2020年第2期27卷 210-219页

作者： Fan zeng xue-jiao Bai Cheng-liang Hu Min-jun Tang Zhen Zhao Institute of Forming Technology and Equipment School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200030China National Engineering Research Center of Die&Mold CAD Shanghai Jiao Tong UniversityShanghai 200030China Jiangsu Longcheng Precision Forging Co. Ltd.Changzhou 213000China

Claw poles are a key component of automobile *** output power performance of the generator is very dependent on the magnetic properties of its claw *** deformation is known to significantly change the magnetic behavior of ferromagnetic materials in claw *** this paper,changes in the magnetic properties of low-carbon steel,used for claw pole components due to their plastic deformation,were investigated for different strains and ***-shaped material samples were prepared by machining and their magnetic properties were *** surface roughness was first evaluated and a machining process with an arithmetic average of roughness Ra 1.6μm was selected as enabling the lowest measurement *** loops at different applied magnetic fields of the material were obtained for different plastic strains and forming *** magnetic parameters of magnetic flux density,coercivity,and remanence were obtained and compared with magnetic flux density as the primary *** showed that machining,cold forming,and hot forming all led to lower magnetic flux density,larger coercivity,and smaller *** flux density showed a sharp decrease at the start of plastic deformation,but as the strain increased,the decreasing trend gradually reached a constant *** decrease was much larger for cold forming than for hot *** example,at 500 A/m,the degradation of magnetic flux density with a reduction percentage of 5%at room temperature was about 50%,while that of hot forming at 1200°C was about 10%.Results of this research may provide a reference for the future process design of hot-forged claw poles.

关键词： low-carbon steel magnetic properties hot forming cold forming surface roughness

Radiation-induced osteosarcoma of the maxilla and mandible after radiotherapy for nasopharyngeal carcinoma

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Chinese Journal of Cancer 2016年第11期35卷 625-631页

作者： Lie-Qiang Liao Hong-Hong Yan Jun-Hao Mai Wei-Wei Liu Hao Li Zhu-ming Guo Zong-Yuan zeng xue-Kui Liu State Key Laboratory of Oncology in South China Collaborative Innovation Center for Cancer MedicineSun Yat-sen University Cancer Center Department of Head and Neck Surgery Sun Yat-sen University Cancer Center651 Dongfeng Road East

Background:The increasing incidence of radiation-induced osteosarcoma of the maxilla and mandible(RIOSM) has become a significant problem that can limit long-term *** purpose of this study was to analyze the association of clinicopathologic characteristics with treatment outcomes and prognostic factors of patients who developed RIOSM after undergoing radiotherapy for nasopharyngeal carcinoma(NPC).Methods:We reviewed the medical records of 53,760 NPC patients admitted to Sun Yat-sen University Cancer Center during the period August 1964 to August *** these patients,47 who developed RISOM and met inclusion criteria were included in this *** of these 47 patients refused treatment and were then ***:For all patients treated for NPC at Sun Yat-sen University Cancer Center during the study period,the total incidence of RIOSM after radiotherapy was 0.084%(47/53,760).Two patients(4.4%) had metastases at the diagnosis of ***-nine of the 45(86.7%) patients underwent surgery for RIOSM;most patients(24/39;61.5%) who underwent resection had gross clear margins,with 15 patients(38.5%) having either a gross or microscopic positive *** patients *** 1-,2-,and 3-year overall survival(OS) rates for the entire cohort of 45 patients were 53.3%,35.6%and 13.5%,*** independent prognostic factors associated with high OS rate were tumor size and treatment ***:RISOM after radiotherapy for NPC is aggressive and often eludes early detection and timely *** combined with postoperative chemotherapy might be an effective treatment to improve patient survival.

关键词： Radiation-induced osteosarcoma Maxilla and mandible Nasopharyngeal carcinoma Prognosis

The multikinase inhibitor sorafenib induces caspase-dependent apoptosis in PC-3 prostate cancer cells

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Asian Journal of Andrology 2010年第4期12卷 527-534页

作者： Rui Huang xue-Qin Chen Ying Huang Ni Chen Hao zeng Department of Nuclear Medicine National Key Discipline of Medical Imaging and Nuclear Medicine West China Hospital Sichuan University Chengdu 610041 China Laboratory of Pathology State Key Laboratory of Biotherapy West China Hospital Sichuan University Chengdu 610041 China Department of Urology West China Hospital Sichuan University Chengdu 610041 China

The present study investigated the effects of the multikinase inhibitor sorafenib on androgen-independent can- cer cells viability and intracellular signaling. Human androgen-independent PC-3 prostate cancer cells were treated with sorafenib. At concentration that suppresses extracellular signal-regulated kinase phosphorylation, sorafenib treatment reduced the mitochondrial transmembrane potential. Sorafenib also down-modulated the levels of mye- loid cell leukemia 1, survivin and cellular inhibitor of apoptosis protein 2. Sorafenib induced caspase-3 cleavage and the mitochondrial release of cytochrome c. However, no nuclear translocation of apoptosis inducing factor was detected after treatment and the pan-caspase inhibitor Z-VAD-FMK had an obvious protective effect against the drug. In conclusion, sorafenib induces apoptosis through a caspase-dependent mechanism with down-regulated antiapoptotic proteins in androgen-independent prostate cancer cells in vitro.

关键词： apoptosis PC-3 prostate cancer cells prostate cancer sorafenib